Getting the Back Key to Work in a Custom Toolbar

Question

I created a toolbar with its own XML layout file. I include the toolbar in the activity_main layout file. In the secondary activity, where the back key on the toolbar should appear, I write:

getSupportActionBar().setHomeButtonEnabled(true);
getSupportActionBar().setDisplayShowHomeEnabled(true);

I also tried:

getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayShowHomeEnabled(true);
getSupportActionBar().setHomeButtonEnabled(true);

For both, the back arrow appears but does nothing when pressed.

if you need more info some of my .java files are below:

MainActivity:

import android.content.Intent;
import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;

public class MainActivity extends AppCompatActivity  {

    private Toolbar toolbar;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        toolbar = (Toolbar) findViewById(R.id.app_bar);
        setSupportActionBar(toolbar);


        // Get the ViewPager and set it's PagerAdapter so that it can display items
        ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
        viewPager.setAdapter(new MainFragmentPageAdapterForTabs(getSupportFragmentManager(),
                MainActivity.this));

        // Give the SlidingTabLayout the ViewPager
        SlidingTabLayout slidingTabLayout = (SlidingTabLayout) findViewById(R.id.sliding_tabs);
        // Center the tabs in the layout
        slidingTabLayout.setDistributeEvenly(true);
        slidingTabLayout.setViewPager(viewPager);

    }

    public void bodyButtonAction(View view){
        Intent intentBody = new Intent(MainActivity.this, SecActivityBody.class);
        startActivity(intentBody);
    }

    public void mindButtonAction(View view){
        Intent intentMind = new Intent(MainActivity.this, SecActivityMind.class);
        startActivity(intentMind);
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }


}

My secondary activity where the back arrow should go:

import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;


public class SecActivityBody extends AppCompatActivity {

    private Toolbar toolbar;
    //private RecyclerView recyclerView;
    //private SecAdapterBody bodyAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_sec_activity_body);
        toolbar = (Toolbar) findViewById(R.id.app_bar);
        setSupportActionBar(toolbar);

        getSupportActionBar().setHomeButtonEnabled(true);
        getSupportActionBar().setDisplayShowHomeEnabled(true);


        // Get the ViewPager and set it's PagerAdapter so that it can display items
        ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
        viewPager.setAdapter(new SecFragmentPageAdapterForBody(getSupportFragmentManager(),
                SecActivityBody.this));

    }

activity_main.xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.integrativestudios.application.recommender.MainActivity">

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <include
            android:id="@+id/app_bar"
            layout="@layout/app_bar" />

        <com.integrativestudios.application.recommender.SlidingTabLayout
            android:id="@+id/sliding_tabs"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />

        <android.support.v4.view.ViewPager
            android:id="@+id/viewpager"
            android:layout_width="match_parent"
            android:layout_height="0px"
            android:layout_weight="1"
            android:background="@android:color/white" />

    </LinearLayout>

</RelativeLayout>

secondary xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.integrativestudios.application.recommender.SecActivityBody">

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <include
            android:id="@+id/app_bar"
            layout="@layout/app_bar" />

        <android.support.v4.view.ViewPager
            android:id="@+id/viewpager"
            android:layout_width="match_parent"
            android:layout_height="0px"
            android:layout_weight="1"
            android:background="@android:color/white" />


    </LinearLayout>

</RelativeLayout>

Answer 1

You need to specify the code that executes the Up navigation. Don't forget to add the parent-activity meta-data to the android manifest.

public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case android.R.id.home:
            Intent parentIntent = NavUtils.getParentActivityIntent(this);
            parentIntent.setFlags(Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT | Intent.FLAG_ACTIVITY_SINGLE_TOP | Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
            startActivity(parentIntent);
            finish();
            return true;
    }
    return super.onOptionsItemSelected(item);
}

This is what worked for me with launchMode="singleTop", but if it works for you, you can try using NavUtils.navigateUpFromSameTask(this).

Answer 2

In your onOptionsItemSelected() check if the selected button is back by the id,

@Override
public boolean onOptionsItemSelected(MenuItem item) {

      int id = item.getItemId();

      if(id == android.R.id.home)
      {
           //perform your operation
      }

      return super.onOptionsItemSelected(item);
}

Answer 3

You need to set the second activity as the child activity of the main(parent) activity for navigating to the logical parent screen in the app's hierarchy by pressing the Up button in the action bar.

For example, here's how you can declare an activity's parent in the manifest:

<application ... >
...
<!-- The main/home activity (it has no parent activity) -->
<activity
    android:name="com.example.myfirstapp.MainActivity" ...>
    ...
</activity>
<!-- A child of the main activity -->
<activity
    android:name="com.example.myfirstapp.DisplayMessageActivity"
    android:label="@string/title_activity_display_message"
    android:parentActivityName="com.example.myfirstapp.MainActivity" >
    <!-- Parent activity meta-data to support 4.0 and lower -->
    <meta-data
        android:name="android.support.PARENT_ACTIVITY"
        android:value="com.example.myfirstapp.MainActivity" />
</activity>

Then enable the app icon as the Up button by calling setDisplayHomeAsUpEnabled():

public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_displaymessage);

getSupportActionBar().setDisplayHomeAsUpEnabled(true);
// If your minSdkVersion is 11 or higher, instead use:
// getActionBar().setDisplayHomeAsUpEnabled(true);
}